The proposed project involves two major components whose ultimate goal is to elucidate the molecular mechanisms involved in the control of eukaryotic gene transcription. The primary emphasis of the first project is the fractionation and purification of components required for accurate initiation and termination of transcription of the Drosophila histone genes. The approach involves a combination of classical enzymological techniques coupled with selection of the appropriate templates using recombinant DNA technology. Once purification of the components is completed a detailed characterization of their function will be undertaken. The second project involves the application of the in vitro transcription approach to two regulated gene systems of Drosophila. The heat shock genes and a developmentally regulated salivary gland glue protein (located at the 3C genetic locus) will be utilized to attempt reconstruction of the various control mechanisms in vitro. Both gene systems have been well characterized with regard to their respective DNA sequences and transcribed regions. Analysis of the heat shock genes should aid in the understanding of a perhaps more specialized mechanism of gene activation and repression, while the developmentally regulated glue gene at the 3C locus may point the way to tissue specific control mechanism.